Abstract: Objective The aim of this study was to investigate the changes and clinical implication of serum procalcitonin (PCT) and interleukin-6 (IL-6) levels in patients with biliary tract stone after stone removal under endoscopic retrograde cholangiopancreatography (ERCP). Methods 142 patients with common bile duct stones and 120 healthy persons were enrolled in this study between July 2010 and July 2020, and all patients underwent stone removal under ERCP. Serum PCT and IL-6 were detected by enzyme-linked immunosorbent assay and double-antibody sandwich immunoluminescence assay. The forecasting value of serum parameters was evaluated by area under receiver operating characteristic curve (AUC). Results Before operation under ERCP, serum PCT, IL-6 levels, peripheral blood white blood cell (WBC) counts, serum ALT, bilirubin and GGT levels in 142 patients with biliary tract stone were (5.1±1.8)μg/L, (63.8±18.3)pg/mL, (13.7±2.8)×10⁹/L, (86.8±8.8)U/L, (49.4±16.6)μmol/L and (89.5±22.7)U/L, they decreased to (2.5±1.9)μg/L, (31.9±12.2)pg/mL, (6.5±3.1)×10⁹/L, (79.2±5.3)U/L, (13.0±3.3)μmol/L and (56.8±14.8)U/L three days after operation, but all significantly higher than [(0.3±0.1)μg/L, (25.0±8.2)pg/mL, (5.2±0.8)×10⁹/L, (18.7±6.8)U/L, (8.3±2.7)μmol/L and (24.2±6.1)U/L, respectively, P＜0.05] in control; the post-operational biliary infections occurred in 18 cases(12.7%) out of our series, and the Gram-negative and Gram-positive bacteria accounted for 83.3% and 16.7%, respectively; serum PCT, IL-6 and peripheral blood WBC counts in patients with biliary infection were (4.9±1.1)μg/L, (52.3±10.6)pg/mL and (11.4±1.3)×10⁹/L, all significantly higher than [(0.1±0.0)μg/L, (28.9±8.2)pg/mL and (5.8±2.1)×10⁹/L, respectively, P＜0.05] in those without infection; the ROC analysis showed that the sensitivity (Se) and specificity (Sp) were 91.8% and 74.3% by serum PCT, 95.4% and 80.5% by serum IL-6, and 94.1% and 78.1% by WBC counts, but they increased to 93.2% and 91.1% by the three combination, significantly higher than anyone alone (P＜0.05) in predicting biliary infection after the stone removal under ERCP. Conclusion The surveillance of serum PCT and IL-6 levels might help predict the biliary infection in patients with cholelithiasis after stone removal under ERCP, and guide clinical management early and appropriately.

Key words: Cholelithiasis, Endoscopic retrograde cholangiopancreatography, Procalcitonin, Interleukin-6, Biliary infection